In recent years, with increasing environmental consciousness, more and more products are designed in views of energy conservation and carbon reduction policy. Consequently, government organizations, enterprises, schools or families pay much attention to the reduction of the frequency and time period of using the air conditioners. For maintaining air circulation and increasing space utilization, a variety of new fans and recirculation fans are introduced into the market.
For most fans, a motor is employed to drive rotation of the fan blades and produce airflow. Consequently, the convection within the indoor construction site will be enhanced and the indoor temperature can be controlled. The mainstream of the indoor recirculation fan is for example a hanging-type fan or a top-embedded fan.
However, due to the spatial and position limitation, the performance of such recirculation fan is usually unsatisfied. In addition, if the amount of the airflow required for indoor convection is increased, the fan should have a longer and larger fan blade. Correspondingly, a large-power and large-size motor is used to provide sufficient torque to rotate the fan. For complying with the large-size motor, the volume of the fan should be largely increased. Under this circumstance, the regions unable to inhale or exhale the airflow will be increased, and the space utilization is deteriorated. In addition, since the overall power consumption is largely increased, it is difficult to achieve the energy conservation and carbon reduction purpose. In other words, the process of deploying the conventional recirculation fan is complicated and the layout cost is increased.